By Ives Galarcep

A year ago, Pablo Mastroeni was in the starting lineup for the Colorado Rapids on opening day. On Saturday, he was on the sideline as Rapids head coach, ready for a new challenge.

HARRISON, N.J.-- Pablo Mastroeni stood on the grass at Red Bull Arena wearing purple as the Colorado Rapids took the field. The big difference from a year ago, when he started as a midfielder in the Rapids' season opener, was that now Mastroeni was wearing a sweater and preparing for his first match as a pro head coach.

Just three months after ending his 16-year professional career as a player, Mastroeni became the latest MLS alumnus to trade in spikes for a place on the touchline and his debut provided some evidence to suggest he just might be one of ones to make a career out of it.

The former World Cup veteran and MLS Cup champion helped guide the Rapids to a season-opening 1-1 tie against the New York Red Bulls at Red Bull Arena, and while the Rapids looked like they might be run out of the building after a slow first 15 minutes, Colorado eventually settled down and stood toe-to-toe with the defending MLS Supporters' Shield winners.

"Knowing Pablo as well as I do, his team at times really reflected the type of person he is," said Red Bulls coach Mike Petke, a former teammate of Mastroeni's. "All-in, fiery, hardworking and Pablo had some talent with the ball too.

"I know what he's going through. We recently spoke over the last week and I'll probably grab a beer with him in the locker room after this and we'll talk some more," said Petke, who was himself a first-year pro coach just a year ago. "I know exactly what he's going through and there's going to be ups and downs for him, and today I guess you could look at it from their standpoint and say it was an up."

While Mastroeni looks different than the dreadlock-wearing national team player of a dozen years ago--he now wears a grey-speckled short haircut-- the 37-year old coach isn't very different according to players who have transitioned from being teammates to players he now leads.

"He hasn't changed much, to be honest, from a player to a coach," said Rapids captain Drew Moor. "I feel like in his last two or three seasons he was a bit of a coach when he was on the field. What he said to players then is the same thing he's saying to us players now.

"He's very passionate. He's always thinking. He's just a smart soccer guy and he knows what he wants out of this team, which is important," Moor said. "He's played with most of us, and he hasn't changed much."

Mastroeni has won over a locker room that could have been tough to win over after the surprising departure of Oscar Pareja, who left Colorado to take over as FC Dallas head coach. Mastroeni, who left the Rapids for the LA Galaxy midway through the 2013 season, returned to the Rapids over the winter as an assistant, but took over the team and ran it as head coach even though the team didn't formally hand him the head coaching job until last week.

"Pablo made a decision from day one, when he came in and started to lead the first team, he made it his team," Moor said. "He didn't act like it was up in the air. We all bought in right away and he wanted us to buy in right away, and I think that was important because once he finally did sign we didn't miss a beat."

Though he has no head coaching experience, Mastroeni has studied the profession going as far back as his college days. He kept a diary of his former coaches through the years, recording the best and worst from each of them, and he has tried to incorporate what he has learned through his 16 years as a player.

"I believe in myself as a leader, first and foremost, and I believe in myself as a student of the game," Mastroeni said. "I have the utmost confidence in myself to be able to communicate effectively the type of soccer we want to play, the philosophies I believe in. The tactics are important as well.

"I think my ability to communicate gives me confidence. It might take a while to get there but I believe we're going to have a good team."

Mastroeni made what some considered some head-scratching moves in his first game in charge, most notably starting young midfielder Dillon Serna on the road ahead of veteran options like Vicente Sanchez. Mastroeni stood by those decisions, stating rather emphatically that he believes in young American players and has confidence in his younger players being able

"I'm an ability guy. Can you do it? Can you get the job done," Mastroeni said. "There are good American players everywhere, you've just got to believe, and there are very good young Americans who have ability in this league. It just seems like fans of American soccer don't give guys an opportunity unless they're already at an Arsenal or Bayern Munich."

Petke and Mastroeni had a chance to speak in the week leading up to Mastroeni's debut and Petke offered his former teammate some good advice about what lies ahead.

"One of the first things he spoke to me about was that you're never off duty, you're never away," Mastroeni said. "One of the more important thing he says, and Jason Kreis said the same thing as well, is to stay true to what you believe."

"The amount of work that you put into it was eye-opening," Mastroeni said. "For me, I never worked more than three hours a day in my life. To now work 10-12-hour days, whether it's watching videos, being tuned in and thinking about the team and the game, is probably something I never thought I would do.

"But when you're passionate about your job and you want to get better at your job, there's times I don't want to come home because I'm so involved. That part has really shocked me in a positive, and for my wife, in a negative way."

Mastroeni's passion for his new job showed in the way his team responded in his debut, and if the Rapids can build on their success in 2013, it will be due in large part to Mastroeni making a smooth transition from the field to the sideline.